Investigating potential hydrological ecosystem services in urban gardens through soil amendment experiments and hydrologic models

Abstract

Among the ecosystem services provided by urban greenspace are the retention and infiltration of stormwater, which decreases urban flooding, and enhanced evapotranspiration, which helps mitigate urban heat island effects. Some types of urban greenspace, such as rain gardens and green roofs, are intentionally designed to enhance these hydrologic functions. Urban gardens, while primarily designed for food production and aesthetic benefits, may have similar hydrologic function, due to high levels of soil organic matter that promote infiltration and water holding capacity. We quantified leachate and soil moisture from experimental urban garden plots receiving various soil amendments (high and low levels of manure and municipal compost, synthetic fertilizer, and no inputs) over three years. Soil moisture varied across treatments, with highest mean levels observed in plots receiving manure compost, and lowest in plots receiving synthetic fertilizer. Soil amendment treatments explained little of the variation in weekly leachate volume, but among treatments, high municipal compost and synthetic fertilizer had lowest leachate volumes, and high and low manure compost had slightly higher mean leachate volumes. We used these data to parameterize a simple mass balance hydrologic model, focusing on high input municipal compost and no compost garden plots, as well as reference turfgrass plots. We ran the model for three growing seasons under ambient precipitation and three elevated precipitation scenarios. Garden plots received 12–16% greater total water inputs compared to turfgrass plots because of irrigation, but leachate totals were 20–30% lower for garden plots across climate scenarios, due to elevated evapotranspiration, which was 50–60% higher in garden plots. Within each climate scenario, difference between garden plots which received high levels of municipal compost and garden plots which received no additional compost were small relative to differences between garden plots and turfgrass. Taken together, these results indicate that garden soil amendments can influence water retention, and the high-water retention, infiltration, and evapotranspiration potential of garden soils relative to turfgrass indicates that hydrologic ecosystem services may be an underappreciated benefit of urban gardens.

Analysis of Supply–Demand Relationship of Cooling Capacity of Blue–Green Landscape under the Direction of Mitigating Urban Heat Island

“…The results of the CESL and CEDL were divided into seven types via a natural breakpoint method: extremely low supply/demand (1), low supply/demand (2), relatively low supply/demand (3), medium supply/demand (4), relatively low supply/demand (5), high supply/demand (6), and extremely high supply/demand (7). And we divided the coordination types into the following seven levels: extreme dissonance (0 < CCD < 0.2), moderate dissonance (0.2 ≤ CCD < 0.3), mild dissonance (0.3 ≤ CCD < 0.4), borderline dissonance (0.4 According to the spatial distribution of the LULC from 2001 to 2021 (Table 7 and Figure 4b), the cultivated land and NBGS areas were the most dominant landscapes in the urban areas, and were also the main landscape types used in land use transfer.…”

“…Artificial impervious surface and greenhouse gases enhance the surface sensible heat flux [2,3]. This has negative effects on urban regional climates [4,5], hydrological characteristics [6], physical and chemical soil characteristics [7], atmospheric environments [8], energy metabolisms [9,10], and residents' health [11][12][13]. The contradictions and conflicts of urban gray infrastructures and blue-green infrastructures formed by impervious surfaces have triggered a series of urban environmental problems [14], which have led to a further aggravation in the intensity of UHIs and have thus formed a vicious circle [15][16][17].…”

A Review of Nutrient Losses to Waters From Soil- and Ground-Based Urban Agriculture—More Nutrient Balances Than Measurements

“…On the other hand, by being a pervious land-use in a "sea of concrete, " UA can help to reduce stormwater runoff such as has been shown in urban vacant lots (Kelleher et al, 2020). In addition, the high infiltration and evapotranspiration potential of UA highlights the benefits gardens can have to the cities' hydrological ecosystem (Chapman et al, 2022). Although the above examples demonstrate that the unique context of cities is likely to mediate nutrient losses from UA, the studies in this review did not explicitly account for how the urban setting of gardens may impact losses to waters.…”

The effect of green stormwater infrastructures in urban tier human thermal comfort—a case study in high-density urban blocks

“…In addition, the cooling effect of the rain garden (RG), a special form of green space, which retains rainwater through lower planes and permeable structures, has been veri ed in several studies (Sadeghi et al 2019). Previous studies have focused mostly on its plant species composition, species characteristics (Bruner et al 2023), and rainwater in ltration e ciency (Buzzard et al 2021;Chapman et al 2022;Kasprzyk et al 2022;Burszta-Adamiak et al 2023). Finally, surface heating can be alleviated by special ground materials (Qin 2015;Seifeddine et al 2023;Yang et al 2023), such as materials or coatings with high re ectivity, which can reduce surface temperature (Kousis and Pisello 2023) to obtain a so-called cold surface.…”